1. Field of the Invention
The present invention relates to an image display apparatus, an image display method and an image display program product, and particularly to an image display apparatus, an image display method and an image display program product displaying an image while retaining confidentiality thereof.
2. Description of the Related Art
In an image processing apparatus such as an MFP (Multi Function Peripheral), a printer, a copying machine, and the like, an image display apparatus such as a display panel has been made larger as the function is more sophisticated or an operation is more complicated. At the same time, considering operability, the image display apparatus has increasingly been arranged at a position readily viewed from the front of the apparatus, for example, in a document holding portion provided above the apparatus or on the front face of the apparatus.
A user can thus readily check display for operation on the image display apparatus, and the operability of the image processing apparatus is improved. In addition, a technology for upsizing an LCD (Liquid Crystal Display) mostly used in the image display apparatus has improved and visibility thereof has also been enhanced. Therefore, operability is further enhanced by mounting a large-size image display apparatus on the image processing apparatus.
Such upsizing of the image display apparatus of the image processing apparatus specifically permits an operation to display image data, obtained by scanning or by reception from another apparatus, for preview prior to output so as to check the contents, orientation, or the like.
If the image data is displayed for preview on the image display apparatus that has been upsized and arranged at a readily viewable position as described above, however, the preview display may be seen by an unintended third party, for example, from behind the user. In addition, if the user leaves the image processing apparatus as well, the preview display may be seen by an unintended third party.
As a technology to prevent leakage of display contents on the image display apparatus, for example, Japanese Laid-Open Patent Publication No. 11-052942 (hereinafter, referred to as Patent Document 1) discloses a technology of such bus control as suppressing reading of a non-display region designated in advance at the time when display data is read from a memory. In addition, Japanese Laid-Open Patent Publication No. 06-290251 (hereinafter, referred to as Patent Document 2) discloses a technology to analyze image data, detect character string that should be kept secret, and mask such portion. Moreover, Japanese Laid-Open Patent Publication No. 02-048857 (hereinafter, referred to as Patent Document 3) discloses a technology to designate a region to be masked in image data and to convert that region to a prescribed color.
If the technology disclosed in Patent Document 1 or the technology disclosed in Patent Document 2 described above is applied to the image display apparatus of the image processing apparatus, however, the processing in the image display apparatus becomes complicated. Consequently, a processing time longer than in the case where such processing is not performed is necessary, or a high-performance apparatus is necessary, which leads to higher cost.
Alternatively, if the technology disclosed in Patent Document 3 described above is applied to the image display apparatus of the image processing apparatus, an operation to designate the region to be masked is necessary, which leads to poorer operability.
Moreover, in the case of a fixed-format image, analyzing the image or performing an operation to set a non-display region each time results in increased complexity in the apparatus and the operation.
Further, an amount of data of an original image is increased due to masking or the like.
As described above, when the image display apparatus of the image processing apparatus is upsized and preview display of image data on the same is attempted, it is difficult to retain security with an easy and simplified configuration.